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Hysteresis of soil moisture spatial heterogeneity and the “homogenizing” effect of vegetation
Author(s) -
Ivanov Valeriy Y.,
Fatichi Simone,
Jenerette G. Darrel,
Espeleta Javier F.,
Troch Peter A.,
Huxman Travis E.
Publication year - 2010
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2009wr008611
Subject(s) - environmental science , water content , storm , spatial heterogeneity , soil science , vegetation (pathology) , hydrology (agriculture) , spatial variability , ecohydrology , drainage basin , moisture , biosphere , spatial ecology , geology , ecosystem , ecology , meteorology , geography , medicine , oceanography , statistics , geotechnical engineering , mathematics , cartography , pathology , biology
By partitioning mass and energy fluxes, soil moisture exerts a fundamental control on basin hydrological response. Using the design characteristics of the Biosphere 2 hillslope experiment, this study investigates aspects of soil moisture spatial and temporal variability in a zero‐order catchment of a semiarid climate. The hydrological response of the domain exhibits a particular structure, which depends on whether topography‐induced subsurface stormflow is triggered. The occurrence of the latter is conditioned by topography, soil depth, and pre‐storm spatial distribution of moisture. As a result, a non‐unique behavior of soil moisture spatial heterogeneity emerges, manifested through a hysteretic dependence of variability metrics on mean water content. Further, it is argued that vegetation dynamics impose a “homogenizing” effect on pre‐storm moisture states, decreasing the likelihood that a rainfall event will result in topographic redistribution of soil water. Consequently, post‐rainfall soil moisture dynamics associated with the effect of topography that could lead to the enhancement of spatial heterogeneity are suppressed; a potential “attractor” of catchment states emerges. The study thus proposes several hypotheses that will be testable within the framework of long‐term hillslope experiments.